Exretion In Human Flashcards
Function of kidney
Removal of urea and excess water and the reabsorpiton of some salt and glucose
Define excretion in human
Removal from organisms of toxic materials, the waste product of metabolism and substances in excess of requirement. Substance should include co2, urea and salts
How is urea form
From excess amino acid in the liver
What is bladder
A sack in which urine is stored
What is urethra
The tube that carries urine out of the body
What is ureter
Connects kidney to bladder
What is cortex
Brown outer area
What is medulla and pelvish
Reddish inner area
White area
Where do alcohol, drugs and hormones break down
Liver
Describe the structure of a kidney
Cortex - brown outer area
Medulla - reddish inner area
Pelvis- a white area
How blood travel in a kidney tubule
Blood containing waste chemicals flows into the kidney in renal artery
Inside the kidney, the renal artery branches many times to give smaller arteries
Each of these arteries supplies blood to a closely packed group pf capillaries called a glomerulus
After filtration, blood flows out of the glomerulus into another small artery and flows in capillaries around the rest of the tubule which joins to form renal vein
Structure of a kidney tubule
Bowman’s (renal) capsule in the cortex
Then the tubule forms a loop which goes deep into the medulla and back to the cortex
The end of the kidney tubule drains into a collecting duct which goes through the medulla and empties into the pelvis
Urine collects in the pelvis and then flows into the ureter
Describe filtration and reabsorption
The lining of capillaries is like a net with tiny holes -> blood cell and large molecules like proteins are to big to pass through -> stay in the blood
Small molecules like urea, glucose, salts and water pass out of the glomerulus and into the bowman capsule which is a place where filtrate collect
All the glucose, some salt and much of water are needed by the body -> reabsorbed into the blood from the kidney tubule
What is left is urea and excess salts dissolved in water
As this fluid flow through the tubule, some more water may be reabsorbed if the body is low on water, creating a concentration in the urine
The fluid then flows down the collecting duct and then to the ureter and the bladder
The blood, with lower concentration of waste chemicals leave the kidney in renal vein
Role of renal capsule
Filtration from blood of water, glucose, urea and salts
Role of tubule
Reabsorption of glucose, most of water and some salts back into the blood, leading to a concentration in urine as well as loss of excess water and salts
